Comparative study on direct and indirect bracket bonding
techniques regarding time length and bracket detachment
Jeferson Vinicius Bozelli1, Renato Bigliazzi1, Helga Adachi Medeiros Barbosa2,
Cristina Lucia Feijo Ortolani3, Francisco Antonio Bertoz4, Kurt Faltin Junior3
How to cite this article: Bozelli JV, Bigliazzi R, Barbosa HAM, Ortolani CLF, Bertoz FA, Faltin Junior K. Comparative study on direct and indirect bracket bonding techniques regarding time length and bracket detachment. Dental Press J Orthod. 2013 Nov-Dec;18(6):51-7.
Submitted: March 02, 2011 - Revised and accepted: February 02, 2012
Contact address: Renato Bigliazzi Faculdade de Odontologia de Araçatuba
Rua José Bonifácio, 1193 – Araçatuba/SP – CEP: 16.015-050 E-mail: bigliazzir@hotmail.com
» Patients displayed in this article previously approved the use of their facial and in-traoral photographs.
1 Associate Professor, Department of Orthodontics, Paulista University (UNIP). 2 MSc in Orthodontics, UNIP.
3 Full professor, Department of Orthodontics Paulista University (UNIP). 4 Full professor, Department of Orthodontics, State University of São Paulo
(UNESP).
» The authors report no commercial, proprietary or inancial interest in the prod-ucts or companies described in this article.
Objective:The aim of this study was to assess the time spent for direct (DBB - direct bracket bonding) and indirect (IBB - indirect bracket bonding) bracket bonding techniques. The time length of laboratorial (IBB) and clinical steps (DBB and IBB) as well as the prevalence of loose bracket ater a 24-week follow-up were evaluated. Methods: Seven-teen patients (7 men and 10 women) with a mean age of 21 years, requiring orthodontic treatment were selected for this study. A total of 304 brackets were used (151 DBB and 153 IBB). The same bracket type and bonding material were used in both groups. Data were submitted to statistical analysis by Wilcoxon non-parametric test at 5% level of signiicance. Results: Considering the total time length, the IBB technique was more time-consuming than the DBB (p < 0.001). However, considering only the clinical phase, the IBB took less time than the DBB (p < 0.001). There was no signiicant diference (p = 0.910) for the time spent during laboratorial positioning of the brackets and clinical ses-sion for IBB in comparison to the clinical procedure for DBB. Additionally, no diference was found as for the preva-lence of loose bracket between both groups. Conclusion: the IBB can be suggested as a valid clinical procedure since the clinical session was faster and the total time spent for laboratorial positioning of the brackets and clinical procedure was similar to that of DBB. In addition, both approaches resulted in similar frequency of loose bracket.
Keywords:Corrective orthodontics. Orthodontic brackets. Dental bonding. Dental detachment.
Objetivo:avaliar o tempo necessário para realização da colagem de braquetes pelas técnicas direta (CDB) e indire-ta (CIB), mensurando o tempo despendido entre a parte laboratorial (CIB) e a parte clínica (CDB e CIB), e a preva-lência de descolamentos durante o período de observação de 24 semanas. Métodos: dezessete pacientes (7 homens e 10 mulheres), com idade média de 21 anos, com necessidade de tratamento ortodôntico, foram selecionados para participar desse estudo. Foram utilizados um total de 304 braquetes, sendo que 151 foram colados pela técnica de CDB e 153 pela CIB, com o mesmo tipo de braquete e material de colagem. Os dados foram submetidos ao teste não paramétrico de Wilcoxon, com signiicância de 5%. Resultados: o tempo total para realização da CIB foi maior em relação à CDB (p < 0,001). Levando em consideração apenas a fase clínica, foi observado que o tempo para CIB foi menor em relação a CDB (p < 0,001). A comparação entre o tempo despendido para o posicionamento dos braque-tes em laboratório mais o tempo em clínica para CIB com o tempo em clínica para a CDB revelou que não houve diferença signiicativa (p = 0,910), nem tampouco quanto à prevalência de descolamento dos braquetes. Conclusão:
a CIB apresenta-se como uma utilidade clínica singular, pois o tempo em clínica foi menor que o da CDB. O tempo despendido no posicionamento dos braquetes no laboratório e de execução clínica da CIB foi semelhante ao tempo gasto pela CDB, a quantidade de descolamentos foi semelhante entre as técnicas.
INTRODUCTION
Bonding accessories on tooth surface revolution-ized Orthodontics,making the clinical results easier and more reliable. It solved some of the difficulties encountered in orthodontic banding procedures; such as professional skills, patient’s discomfort result-ing from separators and bandresult-ing, risk to periodontal diseases and cavities, better esthetic acceptance, ma-terial cost and the time spent to make and insert the
bands.1,2,3 Thus, directly bonding accessories on the
enamel became the most common technique used by orthodontists considering that effective bracket bonding is essential for appropriate orthodontic me-chanics. This approach also reduces treatment length and avoids rebonding caused by inappropriate
po-sitioning and/or loose bracket.4 On the other hand,
precise bracket bonding relies on the professional’s experience and accuracy of bonding procedures.
Aiming at improving precision and attaining
ex-cellence in orthodontic procedures, Silverman et al5
developed the indirect bracket bonding (IBB) tech-nique. In this approach, the brackets are previously positioned on casts with water-soluble or interme-diary adhesives, and then transferred to the mouth by means of an individual tray. For these authors, the direct bracket bonding (DBB) technique is time-consuming and the correct positioning of the brackets is difficult to achieve clinically.
Thus, the aim of this in vivo study was to compare
the direct and indirect (tray transferred with fusible
glue6) bracket bonding techniques regarding the time
spent for laboratorial (IBB) and clinical (IBB and DBB) steps and its correlation for the IBB as well as the prevalence of loose bracket.
MATERIAL AND METHODS
Patient selection and study design
Seventeen patients (7 men and 10 women) with a mean age of 21 years, who required orthodontic treatment, were selected for the present prospec-tive study conducted at the college of Dentistry of Paulista University - UNIP/SP from March to June, 2008. Treatment lasted for 2 years. Each subject signed a written informed consent before entering the cohort which was approved by the Paulista Uni-versity-UNIP/SP Institutional Review board (num-ber 122/05 CEP/ICS/UNIP).
Upper and lower dental casts of each patient were obtained after impression with irreversible hydro-colloid (Jeltrate, Dentsply, Brazil) manipulated ac-cording to the manufacturer’s instructions. The im-pressions were rinsed with water for 1 minute, air-dried and then poured with dental stone (Dentsply, Brazil). After stone crystallization (40 minutes), the casts were removed from the impression trays and trimmed. The IBB technique requires working casts with minor irregularities.
Laboratorial step – Fabrication of transferring trays
All laboratorial procedures were conducted by the same operator according to an accurate methodology. Table 1 presents all the acronyms used in this study for laboratorial and clinical steps timings.
The tooth long axis and the gingival-occlusal height of the brackets tubes were determined manu-ally in all patients for correct bracket positioning. The time spent during this procedure was measured by
the software Palmaryclock® v. 23 (Palmarysoft
2002-2004) downloaded into Palm Tungsten T device
(Palm® - Brazil) and recorded (TL1 – Time spent to
determine the height and tooth long axis in the max-illa and mandible during laboratorial step).
The study by Aguirre et al7 was used as reference
to determine the protocol for the IBB technique con-ducted in the present study. The arches were divided into two sections: upper and lower right side (DBB) and upper and lower left side (IBB), and these sides were chosen based on the fact that they enabled di-rect visualization of bracket bonding, since a right-handed operator conducted the research by himself. The bonding procedure was initiated at the left cen-tral incisor and finished at the left second premo-lar in both the maxilla and mandible. Water-solu-ble glue was used and any excess material draining
from the brackets base was removed. The Morelli®
(0.018 x 0.030-in, Bioprogressive technique) metallic brackets were selected for treating all patients.
bonding performed in each hemi-arch. To make the transferring tray (Figs 1 and 2),hot melt adhesive (slightly fluid) was applied to each bracket and to the vestibular surface of each tooth, following the same bonding sequence for the model, in other words, the bonding started from tooth #21 to #25, then from #31 up to #35. After that, additional glue was insert-ed on the incisal and occlusal surfaces of the teeth in order to make a less flexible and harder tray. The time spent for making the transferring trays was also mea-sured and recorded (TL3, time spent for fabrication of the upper and lower transferring trays).
After solidification of the silicone glue (hot melt glue), the casts were hydrated for 1 minute so that the glue could be dissolved and, then, the brackets were transferred with the transferring trays, concluding the laboratorial step of the IBB approach. The total laboratorial time included the time spent for bracket bonding and fabrication/cleaning of the transferring trays (TLt – total laboratorial time for maxilla and mandible), which means that TLt=TL1+TL2+TL3.
Clinical step
The IBB technique was conducted at the upper and lower left side while the right side was selected for the DBB technique (Fig 3). The procedure was timed after prophylaxis (pumice and rubber tip) and enamel etching performed with 37% of phosphoric acid (RMO) following the manufacturer’s instruc-tions since the time spent for this initial step was sim-ilar for both techniques. The self-curing resin (paste
+ liquid – No Mix) Mono Lock 2 (RMO®) was
se-lected for bonding.
For IBB, the etched teeth and transferring trays were dried in order to maintain the chemical and physical properties of the adhesive system. Then, the activator of the bonding material (liquid) was applied on the enamel and brackets mesh positioned into the transferring tray. After that, resin (paste) was inserted on the brackets mesh that was positioned at the hemi-arch of the patient.
The whole process from application of the activator (liquid) on enamel to positioning of the transferring tray
Figure 1 - Fabrication of the transferring tray. Figure 2 - Transferring trays with ideal dimension and thickness.
Figure 3 - Example of brackets bonded by means of DBB and IBB techniques in the maxilla
Table 1 - Acronyms used for diferent laboratorial and clinical time
TL1 Time spent to determine the height and tooth long axis during laboratorial step in maxilla and mandible TL2 Time spent for bracket bonding in the cast in maxilla and mandible
TL3 Time spent for fabrication of transferring trays in maxilla and mandible TLt Total laboratorial time in maxilla and mandible
TCI1 Time spent with IBB during clinical step in maxilla and mandible
TCI2 Time spent for removal and cleaning of the IBB area in maxilla and mandible TCIt Total clinical time for IBB in maxilla and mandible
TCD1 Time spent with DBB in maxilla and mandible
TCD2 Time spent for cleaning of the DBB area in maxilla and mandible TCDt Total time for DBB in maxilla and mandible
Statistical analysis
The Wilcoxon non-parametric test was applied for comparison between the periods, since assump-tion of data normality was rejected. A significance level of 5% was used in all tests.
RESULTS
Based on the statistical analysis carried out, the following results were obtained.
Evaluation of time spent for bracket bonding with DBB and IBB techniques
Considering the total time spent with IBB (TLt+TCIt) and DBB (TCDt) in both jaws, the Wil-coxon test revealed significant difference (p < 0.001) between the groups, which means that IBB was more time-consuming than DBB (Table 2 and Fig 4). However, when only the clinical step was considered, a statistically significant difference (p < 0.001) was also observed, but IBB (TCIt) was less time-consum-ing than DBB (TCDt) (Table 3 and Fig 5).
There was no significant difference (p = 0.910) for the time spent during laboratorial positioning of the brackets (TPBt = TL1+TL2) and clinical step with IBB (TCIt) in comparison to the clinical time with DBB (TCDt) (Table 4 and Fig 6).
Total number of brackets detached with IBB and DBB techniques
After bracket bonding performed with IBB and DBB approaches in both jaws, a 24-week follow-up was conducted for all patients in order to check po-tential loose bracket. A total of 304 brackets were in-serted, including 151 brackets with DBB technique (70 brackets in maxilla and 81 in mandible) and 153 brackets with IBB (72 brackets in maxilla and 81 in mandible). At the end, a total of 18 brackets were de-tached, which represents 5.92% (Table 5 and Fig 7).
Maxilla exhibited a lower number of loose brackets (22.22%) in comparison to the mandible (77.78%), including 4 detachments in the upper arch (3 for IBB and 1 for DBB) and 14 occurrences in the lower arch (8 for IBB and 6 for DBB).
DISCUSSION
The results of the present study demonstrated that the total time spent with the IBB technique (laboratorial was timed and recorded (TCI1 – time spent for clinical
session of IBB technique in maxilla and mandible). The DBB approach was conducted in sequence, from the right central incisor to the right second premolar in both jaws. The whole process of the direct technique was timed (TCD1 – time spent with the DBB technique in maxilla and mandible). The bonding steps were similar to those of the IBB approach: Drying of the etched teeth, application of activator on enamel and bracket mesh, in-sertion of resin on brackets mesh, and positioning it on the teeth. The positioning respected the height of each tooth (Boone bracket positioning gauge).
After DBB, the removal and cleaning of the IBB area was conducted. The transferring tray and the ex-cess resin were removed using the tip of the rubber band insertion tool and a bur for enamel (3M Unitek – California), respectively. This step was also timed and recorded (TCI2 – time spent for removal and cleaning of the IBB area in maxilla and mandible).
The total clinical time for the IBB approach was repre-sented by the time spent for IBB and cleaning step (TCIt – total clinical time spent for IBB technique in maxilla and mandible), which means TCIt = TCI1+TCI2.
The cleaning of the DBB area was also conducted using a bur to remove excess resin on the enamel sur-face (3M Unitek – California). This process was also timed and recorded (TCD2 – time spent for cleaning of the DBB area in maxilla and mandible).
The total clinical time for the DBB approach was represented by the time spent for DBB (tooth by tooth) and cleaning step (TCDt – total clinical time spent for DBB technique in maxilla and mandible), which means TCDt = TCD1+TCD2.
After the clinical step, the patient was submitted to correction of dental positioning through orth-odontic mechanics.
Follow-up
Table 4 - Total time spent for laboratorial and clinical steps with IBB (TPBt+TCIt) and DBB (TCDt).
Time in seconds
Time n Mean ± SD Minimum Maximum Median
IBB
(TPBt+TCIt) 17 885,87 ± 149,31 720 1296 842,00 DBB (TCDt) 17 892,73 ± 116,21 646 1057 914,00
Table 5 - Distribution of the total number of loose brackets in maxilla and mandible regarding time and teeth.
Months
Detachment Technique tooth 1 2 3 4 5 6
IBB
25 0
24 1 1
23 1 1
22 0
21 1 1
DBB
11 0
12 1 1
13 0
14 0
15 0
IBB
35 1 1
34 1 1
33 2 2
32 1 1
31 2 1 3
DBB
41 1 1
42 1 1
43 2 2
44 0
45 1 1 2
Detach. 9 1 2 2 3 1 18
Figure 4 - Comparison of the time spent with IBB (TLt+TCIt) and DBB (TCDt) in the maxilla and the mandible.
1600 1400 1200 1000 800 600 400 200 0
p < 0.001
time
TCDt (DBB) TLt+TClt (IBB)
Figure 5 - Comparison of the time spent with IBB (TCIt) and DBB (TCDt) in the maxilla and the mandible during clinical step.
p < 0.001
time
TCDt (DBB) TClt (IBB) 1200
1000
800
600
400
200
0
Figure 6 - Comparison of the time spent during laboratorial and clinical steps with IBB (TPBt+TCIt) and DBB (TCDt).
p < 0.910
time
1200 1000
800
600
400
200 0
TCDt (DBB) TPBt+TClt (IBB)
Table 3 - Total time spent with IBB (TLt+TCIt) and DBB (TCDt) in both arches, for clinical steps.
Time in seconds.
Time n Mean ± SD Minimum Maximum Median
IBB (TCIt) 17 380,13 ± 47,59 315 489 376,00
DBB (TCDt) 17 892,73 ± 116,21 646 1057 914,00
Time n Mean ± SD Minimum Maximum Median
IBB
(TLt+TCIt) 17 1167,20 ± 239,39 961 1913 1092,00 DBB
(TCDt) 17 892,73 ± 116,21 646 1057 914,00
Table 2 - Total time spent with IBB (TLt+TCIt) and DBB (TCDt), in both arches.
Time in seconds.
Figure 7 - Total number of detachments with IBB and DBB techniques in the maxilla and the mandible.
DBB up. 8
1
6
3
IBB up. DBB low.
and clinical steps) was signiicantly longer than that with the DBB approach, which is in agreement with other
authors3,6-9. The mean total time for IBB (TLt+TCIt)
was 1167.20 seconds, nearly 19.46 minutes to conclude the process from the central incisor to the second pre-molar at the let side (maxilla and mandible). If this value were doubled, a total of 38.92 minutes would be spent to complete de IBB procedure in the whole mouth.
As for the DBB technique, a mean time of 892.73 seconds was used to complete the process (TCDt), nearly 14.88 minutes for bonding from the central incisor to the second premolar at the right side (max-illa and mandible). Again, if this value were double, a total of 29.76 minutes would be necessary to accom-plish the DBB procedure in the whole mouth.
Thus, the time spent with both IBB and DBB techniques in the present study was shorter than that
reported by other researches.7,9 In this sense, the IBB
procedure can be considered faster due to being con-sidered as an easy technique, demanding fewer labo-ratorial steps and being clinically applied with ease.
With regard to the clinical phase, the present study revealed that the IBB technique was signiicantly less
time-consuming than the DBB.8-11 A mean of 380.13
seconds was necessary to complete the clinical procedure with the IBB (TCIt), representing about 6.33 minutes. Thus, based on the same analogy described previously, the procedure would be completed in 12.68 minutes for the whole mouth. Considering that the total time (laboratorial and clinical steps) for both jaws (maxilla and mandible) was 38.92 minutes, the laboratorial phase rep-resents 67.50% of the IBB technique. However, trained assistants could carry out some of these procedures (fabri-cation and cleaning of the transferring tray), reducing the
diference between IBB and DBB approaches.11
As for DBB, the mean total time in both jaws was 29.76 minutes, longer than time used to perform the clinical step with IBB (12.68 minutes). Thus, the IBB is advantageous in comparison to the DBB since it reduces chair-time for bracket bonding, minimizes
clinical stress and increases patient’s comfort.11
It is important to highlight that the time spent to make the working casts was not considered since it can be obtained at the same session in which diagnostic casts
are made or even at a dental radiology center. However, the other laboratorial steps could not be disregarded.
As for loose brackets, the results demonstrated a value of 5.92% during a 24-week follow-up, which
was similar to previous studies.7,9,12-13 It has been
sug-gested that there is no statistically signiicant diference between the IBB and DBB techniques regarding the
retention of brackets bonded to human enamel.14,15,16
In this sense, the lower teeth exhibited more
fail-ures than the upper teeth.7,17,18,19 However, the
ante-rior teeth presented more detachments in compari-son to the posterior teeth, which is in disagreement
with other studies.17-20 Considering the analysis of
the results and the clinical aspects that could result in a higher prevalence of failure in the lower ante-rior teeth, it was concluded that this data was spe-cific for the present sample. The loose brackets may have been caused by failure during initial impression or positioning (DBB), failure during laboratorial step (IBB), poor tooth polishing, failure during acid etch-ing, poor control of humidity, several contamina-tions (saliva and blood), improper occlusion (contact with orthodontic accessories), repeated trauma (hard
food), and enamel quality.21
Considering the literature and the present results, it was observed that the IBB technique is advanta-geous in comparison to the DBB approach due to easy laboratorial procedure, accurate brackets posi-tioning, reduced chair-time and clinical stress, and multidisciplinary accomplishment (orthodontist and assistants).
CONCLUSIONS
The total time spent with the DBB technique was shorter than that with the IBB approach. However, the clinical step took less time with IBB in com-parison to DBB. The time spent for laboratorial po-sitioning of the brackets and clinical insertion with IBB was similar to that observed with DBB, which justifies the advantages of the IBB technique in com-parison to the DBB procedure.
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